1. Field of the Invention
The present invention relates to a shock-absorbing structure for a heel stopper in an automobile in which a heel stopper member is disposed in a lower part of a dash panel of a vehicle body so as to project rearward from the panel surface, the heel stopper member being capable of engaging with a heel of an occupant in a front seat.
2. Description of the Related Art
When an automobile body receives a large shock from the front due to a head-on collision, etc., an upper part of a dash panel is slightly deformed rearward, and a foot of an occupant in a front seat tends to be pushed forward strongly due to inertia. This causes the heel part of the foot to be pushed forward and the toe part to be pushed rearward, leading to a possibility that a large moment around an axis in the vehicle width direction acts on the ankle.
In a conventionally known arrangement (see, for example, Japanese Patent Application Laid-open No. 2001-219872), a heel stopper member is disposed in a lower part of a dash panel so as to project rearward from the panel surface, and while a front part of the member is secured to the dash panel, a rear part thereof can slide on a floor panel. When an upper part of the dash panel is deformed rearward due to the shock of a collision, the heel stopper member is made to slide rearward on the floor panel in association with the deformation, thus restricting forward movement of the heel part to reduce the moment acting on the ankle.
However, in the above conventional arrangement, since the rear part of the heel stopper member is not fastened to the floor panel, the rear part of the heel stopper member may be displaced during assembly, use or a collision. As a result, the heel may not appropriately abut against a heel receiving surface of the heel stopper member, or the heel stopper member may tilt while it is sliding rearward, resulting in the ankle being twisted.
Furthermore, the conventional heel stopper member itself does not have sufficient shock-absorbing ability, and a large shock applied to the heel stopper member may be entirely transferred to the ankle when the dash panel deforms during the collision or if a vehicle body component (for example, a subframe) in front of the dash panel projects toward the heel stopper member.
The present invention has been proposed in view of the above-mentioned circumstances, and it is an object of the present invention to provide an automobile heel stopper shock-absorbing structure that has a simple structure and can solve the above-mentioned problems of the conventional arrangement.
In order to accomplish the above object, a first aspect of the present invention provides an automobile heel stopper shock-absorbing structure in which a heel stopper member is disposed in a lower part of a dash panel of a vehicle body so as to project rearward from the panel surface and be capable of engaging with a heel of an occupant in a front seat, wherein the heel stopper member is formed from a receiving plate that on the outside has a heel receiving surface and on the inside faces the dash panel with a space therebetween, a front support plate connected integrally to a front end part of the receiving plate and having its extremity joined to the dash panel, and a rear support plate connected integrally to a rear end part of the receiving plate and having its extremity joined to at least one of the dash panel and a floor panel, and wherein the rear support plate is made weaker than the receiving plate and the front support plate so that the rear support plate will buckle when a pushing-in load acting on the receiving plate is equal to or greater than a predetermined value, and values of flexural rigidity of the front support plate and the receiving plate are set so that the front support plate falls forward so as to make the receiving plate sink forward when the pushing-in load acting on the receiving plate is equal to or greater than a predetermined value, whereby when a compression load acting between the heel and the receiving plate becomes equal to or greater than a predetermined value due to a collision of an automobile, a shock acting on the heel is primarily absorbed by buckling of the rear support plate, and furthermore is secondarily absorbed by falling-forward of the front support plate.
In accordance with this arrangement, even when the upper part of the dash panel is slightly deformed rearward due to a large shock to the vehicle body from the front when the automobile is involved in a collision, and a foot of the occupant in the front seat is pushed forward strongly due to inertia, since the heel can engage with the heel receiving surface of the heel stopper member, excessive forward movement of the heel can be suppressed. The shock that the heel receives at this time can be primarily absorbed by buckling of the rear support plate of the heel stopper member and, furthermore, secondarily absorbed by the front support plate falling forward and deforming so as to make the heel receiving surface of the heel stopper member sink forward. In this case, since the extremity of the rear support plate of the heel stopper member is joined to at least one of the dash panel and the floor panel and the extremity of the front support plate is joined to the dash panel, there is no possibility of the heel stopper member being significantly displaced relative to the dash panel and the floor panel. Moreover, the angle through which the receiving plate tilts is maintained in a predetermined appropriate angular range by the buckling of the rear support plate and the falling forward of the front support plate, so that the ankle is not forcibly twisted. In this way, the heel can be appropriately engaged with and supported on the heel receiving surface of the receiving plate, thus effectively suppressing the excessive forward movement of the heel. Moreover, when the heel is engaged, the heel stopper member itself deforms (the buckling of the rear support plate and the falling forward of the front support plate), thereby effectively absorbing and alleviating the shock on the heel. As described above, since the shock and the moment around the axis in the vehicle width direction acting on the ankle can be lessened while avoiding forcible twisting of the ankle, the burden on the ankle can be greatly lightened, resulting in a very effective prevention of damage thereto.
Furthermore, in accordance with a second aspect of the present invention, in addition to the first aspect, there is proposed an automobile heel stopper shock-absorbing structure wherein the extremity of the front support plate is secured to the dash panel at two or more positions. In accordance with this arrangement, even when the positions where the front and rear support plates are mounted are offset relative to each other in the lateral direction, or the directions in which forces acting on the two support plates are not uniform, the rigid front support plate and the rigid receiving plate portion of the heel stopper member can be effectively prevented from swinging around the longitudinal axis and tilting laterally, thereby preventing the ankle from being twisted due to the tilting of the receiving plate.
Moreover, in accordance with a third aspect of the present invention, in addition to the first or second aspect, there is proposed an automobile heel stopper shock-absorbing structure wherein a gusset is secured to at least one of the dash panel and the floor panel so as to correspond to a rear end part of a subframe that supports an engine on the vehicle body on the front side of the dash panel, and the extremity of the rear support plate is fixed to a protruding part of the gusset, the protruding part being separate from an upper surface of the floor panel. In accordance with this arrangement, since the rear support plate of the heel stopper member is supported on the vehicle body via the gusset, that is, in a state in which the rear support plate is raised from the upper surface of a front end part of the floor panel, even when the subframe moves forcefully rearward due to the shock of a collision and breaks into the front end part of the floor panel in the automobile in which the subframe is present on the front side of the heel stopper member, it is possible to avoid as much as possible the rear end part of the subframe directly hitting the heel stopper member, thereby enabling the heel stopper member to effectively exhibit desired shock-absorbing and heel supporting functions.
Furthermore, in accordance with a fourth aspect of the present invention, in addition to any one of the first to third aspects, there is proposed an automobile heel stopper shock-absorbing structure wherein the front support plate is connected to the receiving plate at a predetermined angle so as to form therebetween a ridgeline extending in the lateral direction of the vehicle body, downward flanges are formed integrally on at least one of left and right edges of each of the front support plate and the receiving plate, and a notch is formed in the heel stopper member so as to separate the downward flange of the front support plate from the downward flange of the receiving plate and cut into at least one end of the ridgeline. In accordance with this arrangement, while imparting a required rigidity to each of the receiving plate and the front support plate of the heel stopper member by specially providing the downward flanges, it becomes possible to cause folding deformation on the ridgeline between the receiving plate and the front support plate (that is, the falling forward deformation of the front support plate) without difficulty by specially providing the notch.
Moreover, in accordance with a fifth aspect of the present invention, in addition to any one of the first to fourth aspects, there is proposed an automobile heel stopper shock-absorbing structure wherein at least one fold line is formed in a middle section of the rear support plate so as to easily cause the buckling of the rear support plate. In accordance with this arrangement, even when the rear support plate is formed from a plate material, the buckling can be caused without difficulty.
The above-mentioned object, other objects, characteristics, and advantages of the present invention will become apparent from an explanation of a preferred embodiment that will be described in detail below by reference to the attached drawings.